A135999 Numbers that are both triangular numbers A000217 and triangle-shaped numbers A134999.

105, 120, 136, 153, 171, 190, 231, 253, 276, 300, 325, 351, 378, 406, 435, 465, 496, 528, 561, 595, 703, 780, 820, 861, 903, 946, 990, 1596, 1711, 2145, 2346, 3240, 3321, 3486, 3570, 3741, 4371, 4560, 4753, 5565

Offset: 1

Author

Omar E. Pol, Dec 10 2007

Keywords

• base
• nonn

Comments

The number 496 appears to be the unique perfect number A000396 of this sequence. The interesting numbers 120 and 153 are supertriangular numbers.

Examples

			The numbers 120 as a triangle-shaped number A134999:
. 2 .
1 . .
. . 0
The number 120 as a triangular number A000217:
. . . . . . . O
. . . . . . .O O
. . . . . . O O O
. . . . . .O O O O
. . . . . O O O O O
. . . . .O O O O O O
. . . . O O O O O O O
. . . .O O O O O O O O
. . . O O O O O O O O O
. . .O O O O O O O O O O
. . O O O O O O O O O O O
. .O O O O O O O O O O O O
. O O O O O O O O O O O O O
.O O O O O O O O O O O O O O
O O O O O O O O O O O O O O O <--- A000217(15)=120.
		

Crossrefs

Cf. A000217, A000396, A134999, A135600, A135601, A135602, A135603, A135643.